Method and apparatus for dehydrating tar



Oct. 30, 1928. 1,689,309y

A. w. WARNER METHOD AND APPARATUS FOR DEHYDRATING TAR Filed June l2, 1924 Patented Oct. 30, 1928.

UNITED STATES PATENT OFFICE.

METHOD A ND APPARATUS FOR DEHYDRATING- TAR.

Application filed .Tune 12, 1924. Serial No. 719,655.

My invention relates to t-he treatment of emulsions and mixtures of tar or other materials with water and has for its object to provide an economical method and apparatus for eliminating the water from such emulsions and mixtures to at least a Asufficient extent to greatly increase their industrial value. The difculties heretofore met with in dehydrating tars are generally due to the tendencies of such emulsions to a violent frothing on the application of heat. I have discovered that this violent frothing can be avoided and a rapid and economical dehydration of the tars effected by maintaining in circulation a considerable volume of comparatively dry tar, circulation being through a circuit comprising a heater and a spraying chamber into which the heated tars from the heater are delivered and by feeding into the circuit between the spraying chamber and the heater a limited amount of Wet tar, the heat in circulation being so regulated that the mixed tars are raised to a proper degree of temperature before entering the spraying tank, say about 240 F. The percentage of wet tar added to the dry tar should be such as to lower its temperature to a point Where violent frothing will not take place, this being important as it avoids the risk of frothing in the pump by which the tars are kept 1n circulation and this temperature should properly be between 200 and 210 F.

Vhile my invention has special value 1n the dehydration of tar emulsions it is obviously usefully applicable to mixtures of water with other materials.

My method and the apparatus Which I have devised for'carrying it into effect, will be best understood as-desc-ribed in connection with the drawings in which the apparatus is illustrated and in which- Figure 1 is a diagrammatic View of the entire apparatus.

Figure 2, a View on a larger scale of the device used for regulating the feed of wet tar to the circuit, and

Figure 3, a cross section on the line 3-3 of Fig. 2.

A indicates a tar storage tank; B, a pipe leading from this tank to a wet tar pump indicated at C, by which the tar is pumped through the conduit extension B into the Wet tar feed tank indicated at E; D indicating a strainer in the conduit B. B2 is the outlet pipe from the Wet tar tank E which in the construction illustrated, see Fig. 2, opens into a vertical sleeve F, through which extends a tubularextension G of the tank G, such tubular extension having a slot G2 formed in it which registers more or less with the pipe B2. The tank G has arestrigited outlet passage G3 at its bottom and is-s'i'spended by a cord H extending over a pulley H and having an available counterweight H2 attached to it. This device maintains an 65 approximately constant head of tar in tank G as, when the weight of tank G and its contents exceeds that of counterweight H2, the tank moves down and port G2 moves out of registry with pipe B2 cutting off the tar sup- 70 ply until the flow through G3 restores the normal balance. The tank G, as shown, delivers the wet tar into the head .I of a conduit J which opens into a mixing tank indicated at K, from which in turn leads the conduit K connecting With the pump indicated at L and continuing, as indicated at K2, into a heater indicated at M. M indicates the heating coil in this heater and M2 a trap at'the end of the coil for condensed Water. 80

The heater opens, through a conduit M3, into the top of a separator chamber O, preferably having a multiple series of outlet pipes, as indicated at N. The trap O permits the escape of tar from the separator O when it reaches a certain levelv therein, and delivers the tar through a conduit S into a storage tank indicated at S. The water vapors separated in the chamber O pass through a conduit P into a condenser Q, the condensing Water entering at Q and being led off at Q2, and the condensed vapors, oils, etc., are drawn off from time to time through the conduit Q* into a receptacle indicated at R.

In operation theapparatus is charged with dry or comparatively dry tar in quantity sufficient to ll al1 parts of the apparatus except the separator and to partly iill the separator as shown so that when the pump L is in operation all parts ofthe apparatus including the heater and mixing tank are filled with tar except the upper part of the separator, and of course, the condenser Q. This dry tar may be produced by charging the apparatus first with wet tar and dehydrating the heater and through the Spraying .chamber, and from the spraying chamber passes down into the mixing' tank K; the dry tar CSI being raised to a temperature of, say, 210 F., wet tar is fed from the tank E through the apparatus described and in regulated quantity into the tank K, where it mixes with dry tar, naturally lowering its temperature so that when the mixed tars reach the pump L,\there is no tendency to violent frothing in the pump. The mixed tars then pass to the heater M where they are raised to a temperature of about 240 F. and the heated tars are delivered through the multiple outlet pipes N into the top of the spraying chamber O, so that they fall with considerable velocity into the body of tar contained, in the bottom of this chamber. This impingement of the hot tars in separate streams into the tar in the bottom of the chamber, I have found to have an important effect in the separation of the water from the tar. The water vapors m the chamber O are drawn of through the conduit P to the condenser and a quantity of the mixed and dehydrated tars substantially equal to the amount of wet tar added is constantly drawn of through the trap O. In this way the volume of tar in the apparatus remains constant.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. In the Operation of a dehydrating apparatus for liquid comprising a heater, a separator into which the heater delivers the heated liquid, a conduit leading from the separator to the heater and a circulating pump located in said conduit, the method of operating the same for the dehydration of fluid mixtures of liquid mixed with water which consists in circulating a comparatively dehydrated mixture of the liquid throu h the apparatus mixing with said dehy ated liquid as it passes from the separator and before it reaches the pump, a limited amount of the liquid to be dehydrated so as to reduce the temperature of the mixture below a point at which frothing will occur in the pump, raising the temperature of the mixture in the heater to a point at which the water in the mixture passes freely into'vapor form, drawing off separated water vapor from'the se arator and drawing oli' from the mixture a er separation of water and before the addition of fresh liquid to be dehydrated a quantity of the dehydrated liquid substantially equal Asaid conduit, the method of operating the same for the dehydration of tars which consists in circulating a comparatively dehydrated tar through the apparatus, mixing with said dehydrated tar as it passes from the separator and before it reaches the pump a limited amount of wet tar so as to reduce the temperature of the mixture below a point at which frothing will occur in the pump, raising the temperature of the mixture in the heater to a point at which the Water mixed with the tar passes freely into vapor` form, drawing off separated water vapor from the separator and drawing 0E from the tar after separation of water and before thel addition of wet tar to be dehydrateda quantlty of the dry tar substantially equal to the Vamount of the tar added in admixture with water.

3. Apparatus for dehydrating fluid mixtures and material mixed with water, comprising in combination a circuitincluding a separator, a heater with a conduit opening into the top of the separator, a mixing tank located below and connected with the separator, a conduit connecting the mixing tank with the heater and a pump in said last mentioned conduit, means for feeding a mixture to be dehydrated into the mixing tank, means for drawing off water vapor from the separator and means for drawing off dehydrated material from the separator.

ARTHUR w. WARNER. 

